The above map shows the border between the United Arab Emirates (yellow) and Oman (green). Inside the UAE is a tiny enclave of Omanese territory called Madha. It consists of about 29 square miles. Inside that enclave is another enclave of UAE territory called Nahwa, which is under a square mile in area. At the link, you can view pictures of this enclave within an enclave.

In the Netherlands we have Baarle-Hertog and Baarle-Nassau. This is Belgian territory well within the Dutch (Netherlands) borders. Yet within this piece of fine Belgian real-estate, there are some 22 Dutch patches of land.

I used to visit there quite often. There is no offcial border, so it's difficult to know exactly which country you are in. But we finally noticed two give aways: every store will prominently display a portrait of their respective leader, and the UAE lamp posts are much fancier.